I’m tickled to see that my work on stonefly flight has come up in this discussion. One thing that is worth adding here is that a gills-to-wings transition would require a simultaneous change in gas exchange, since a sophisticated wing is unlikely to also be an effective gill, and the physics and physiology of gas exchange are very different in an aquatic versus a terrestrial environment. My research shows that modern stoneflies may have retained intermediate forms of flight that date back to an evolutionary transition from gills to wings, and therefore perhaps they have retained other traits related to a transition in gas exchange physiology. This line of thinking led me to suggest to Thorsten Burmester, an expert on arthropod gas exchange proteins, that he should check to see if stoneflies have hemocyanin in their blood. This was a pretty far out idea, since blood-based gas exchange is what other arthropods use (including aquatic ones) but was previously thought to be completely absent in insects, which deliver air directly to their tissues via tracheae. Burmester found that stoneflies do indeed have hemocyanin in their blood (Proceedings of the National Academy of Sciences 101: 871-874) that reversibly binds oxygen, and it appears that no other pterygote insects possess this trait. In summary, the developmental evidence that you have presented for a gills-to-wings transition is supported by both a set of mechanically intermediate forms of winged locomotion in stoneflies and molecular evidence that a simultaneous transition occurred in gas exchange physiology.

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It might be interesting to anticipate how creationists would use the above note from Marden for a quote mine. For example, it would not surprise me in the least to see some anti-evolutionist, in the very near future, cite a quote like this:

“[a] gills-to-wings transition would require a simultaneous change in gas exchange, since a sophisticated wing is unlikely to also be an effective gill, and the physics and physiology of gas exchange are very different in an aquatic versus a terrestrial environment.”

And then the creationist would go on to produce a bunch of irrelevant facts and junk-science to claim that this is further “evidence against evolution,” while pretending that Marden’s solution to the problem further down in the passage simply doesn’t exist.

This has been a common creationist tactic for so long now that anyone remotely familiar with their literature can probably cite a half-dozen examples off the tops of their heads.

In fact, the WAD shows his common ancestry with other creationists by badly abusing a citation from paleontologist Peter Ward’s book On Methuselah’s Trail, as documented by Gary S. Hurd and Dave Mullenix, and then further by Jason Rosenhouse in the latest Skeptical Inquirer (Nov/Dec 05). I wasn’t able to find a link to Jason’s piece… anyone?

Cool game, skip. Lemme try. Here’s what I would write if I became Steveador Cordova:

Burmester found that stoneflies do indeed have hemocyanin in their blood (Proceedings of the National Academy of Sciences 101: 871-874) that reversibly binds oxygen, and it appears that no other pterygote insects possess this trait. How could stoneflies possess a trait absent in their fellow flies, but present in a gilled species, if it’s more closely related to other flies? Do these scientists expect us to believe that flies evolved from Catfish? Even scientists admit that this is “a pretty far out idea”. The data easily fits the more parsimonious model of an Intelligent Designer doing whatever He chose. Wal-mart has sold approximately 283 billion goldfish. According to the evolutionists, some of those must’ve turned into dragonflies on the way home, I guess.